The WS7 II replaced the WS7 - here is some info from the RB Concepts site.
World champion, European Champion and winner of the most prestigious international races, the famous RB Concept World S7 is becoming an true legend, means the best off road engines of the world.
When Rody Roem and the engine R&D dpt. of RB Products started to develop the successor of the WS7, they have been inspired by all the experience and the knowledge coming from the world-famous World S7. Several years of testing were needed to come to the right balance of the previous WS7 and then new improved WS7II. A new Bi-Turbo crankshaft SQC* has been tested in the most terrible conditions of dust, mud and high temperature. Including the exclusive RB Concept Coating, the new WS7 II has showed the same reliability as its well-known predecessor. Never an engine has been so much tested during the stages of its development! Based upon these technical data of WS7, the new RB Concept World S7 II has also other new technical and exclusive features:
Click here for the exploded view of this engine.
A new big size cooling-head for a perfect cooling under the highest temperatures, a separate combustion chamber, a new composite 9mm carburetor supplied with a 8mm venturi.
1004-WS7II
Contents : 3.49cc
Bore : 16.42mm
Stroke : 16.42mm
Porting intake : 7
Porting exhaust : 1
Crankshaft : 13mm "Bi-Turbo Buggy"
Carburetor : "Nylon" venturi 8mm
Glowplug : #1055-6 "Normal"
Weight : 370Gr.
Advised tuned pipe : #E1351-1263P
Crankcase: This RB Concept WS7II anodized crankcase has been designed and developed internally and externally by Rody Roem. The weight has been kept to a minimum and its cooling capacity's to a maximum, it is more rigid and extra cooling ribs are present on the bottom of the crankcase to get more efficient cooling.
Crankcase-porting: Its unique internal 3-ports design helps the engine to get the best torque available at low rpm and usable power with good fuel-consumption. The moulding of the crankcase is realized with a vacuum system to avoid air cavity's during the moulding process.
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Piston/Liner: The piston/Liner is of the type ABC chromed and rectified, the piston fits with precision in the sleeve to get the best performances and a longer life! The sleeve features 7 intake ports, this sleeve is specially adapted on the porting of the WS7 II using the last technologies available.
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Conrod: The Conrod is manufactured from high quality, ultra sound checked aluminum, it has got 2 special bushings inserted and expanded with the latest technology available. The aerodynamic designed shape is developed to obtain less obstruction in the internal gasflow and a special groove is made for better lubrification performance and reliability.
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Crankshaft: The shape of the new Bi-Turbo SQC* crankshaft gives astonishing performances to the new RB Concept World S7 II ! The timing and gas flow have been specially designed for the off road specifications. The special drawing of the crankshaft has been studied to offer the best weight balance possible.
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Bearings: The front-bearing of this RB Concept World S7 has got a rubber shield to prevent dust or water to come into the engine and deteriorating the bearing itself.
The 13mm rear-bearing is of very high quality and has its line of balls placed more close to the conrod to get a better stability of the crankshaft.
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Cooling-head: The new cooling head has been also re-designed after many tests. Bigger, this new head (with a separate combustion chamber) improves the cooling and keeps continuous performances during the whole race.
Carburetor: This new improved carburetor is mainly made out of Nylon to prevent overheating of the fuel coming into the engine(vaporlock) when it is very hot. The base of the carburetor has a new steel insert which goes through till the top of the housing, so strength and stability is assured.
At the base this 9mm carburetor has a 8mm venturi and can receive also the following venturis of 7, 6 or also 9mm depending the power you need and fuelconsumption you want to obtain.
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Glowplug: The "NORMAL" glowplug RB Concept, specially adapted for off-road use, uses the same wire as the "Turbo" glowplugs used in high competition and recognized to be strong and reliable.
Tuned pipes: In our program we also have available a large range of tuned pipes and manifolds, many of these tuned pipes and manifolds are possible to be used on this engine but every pipe will give the engine a different power-output and performance, this also in combination with the pipe-length used.
Please find our selection of possible RB Concept .21 Pipes and Manifolds.
This RB Concept "WS7II" engine is available in the following configurations
1004-WS7 RB Concept 3.5cc(.21) engine "WS7 II".
E1004-WS7 RB Concept 3.5cc(.21) engine "WS7 II".
Supplied with manifold(1316P), connector(1321) and tuned pipe (1350-63).
E1004-WS71 RB Concept 3.5cc(.21) engine "WS7 II".
Supplied with set "IN-LINE" E1351-1263P
E1004-WS72 RB Concept 3.5cc(.21) engine "WS7 II".
Supplied with set "IN-LINE" E1351-1186P
No further additions needed, this engine is ready for the high competion racing!
